Posted
by
Soulskill
on Saturday July 16, 2011 @11:20PM
from the it's-like-a-helmet-but-with-celery dept.

LesterMoore writes "Japanese company Sumitomo Electric Industries have developed a new material that they believe can significantly improve the capacity of EV batteries. The material is a form of porous aluminum called 'Aluminum-Celmet.' 'The positive electrode current collector in a conventional lithium-ion secondary battery is made from aluminum foil, while the negative electrode current collector is made from copper foil. Replacing the aluminum foil with Aluminum-Celmet increases the amount of positive active material per unit area. Sumitomo Electric’s trial calculations indicate that in the case of automotive onboard battery packs, such replacement will increase battery capacity 1.5 to 3 times. Alternatively, with no change in capacity, battery volume can be reduced to one-third to two-thirds. These changes afford such benefits as reduced footprint of home-use storage batteries for power generated by solar and other natural sources, as well as by fuel cells."

This is Sumitomo Electric, annual sales about US$20 billion, not some startup. Their major businesses are wire and cable, which includes fibre optics and associated laser diodes. Looking back at their press releases, there are items like "Arrival of the "Era of High-Temperature Superconducting Wire with 200-A-Class Critical Current", followed a few months later by "World's First In-Grid High-Temperature Superconducting Power Cable System is Now Online at Albany, New York". This company doesn't typically overhype their technology.

Their "celmet" materials have been around for a while, but until recently, they were nickel-based only. They've made some NiMh batteries with this technology, but there wasn't a big win. Now they have an aluminum version, which is more useful for batteries.

The Sinclair C5 - cool though it was, and I still want one - was a small electric recumbent cycle. Its real range was closer to 25km than 40km, and at a top speed of 25km/h. It had pedals, but then the aerodynamic design was compensated for by carrying around 30kg of deep-cycle lead-acid battery. It needed to charge up overnight from flat, giving about an hour's run time for a full 12 hours of charging.

I'm not a particularly hardcore cyclist, but even I can beat the C5's range and speed, powered only by a pint or two of beer and a couple of pies...

Someone was complaining to me recently about rechargeable D cells only providing the same capacity of AA cells[1]. I told him he should check the capacities before buying them, since all rechargeables list their capacity in mAh on the side. I told him 650mAh was about what he'd expect from an AA, because that was about the most I could find when I last bought AAs. Then I decided to actually check. It turns out that these days 2-3Ah is normal for AA batteries. I used to have a Psion Series 3, which ran on alkaline AA batteries and had a battery monitor that told you how much it had drained - that's more than I got out of alkaline non-rechargeables back then (mid '90s).

It's easy to miss these advances, but I was really surprised how much cheap rechargeables have improved. The other thing that really brought home the improvement to me recently was a toy helicopter that I got for my birthday. I got one a few years ago, but it had a much smaller and lighter body, and didn't fly as long. In the early '90s, I asked about building electric toy helicopters, and was told that there was no power source that would work for them. The person I was talking to went through the calculations - batteries of the time simply did not have the energy density to lift themselves. That was just before LiIon started to become commercially available. Now, not only is it possible, it's so cheap that you can put them in toys for children / geeks. Oh, and as an aside, I also remember seeing the first prototype for a helicopter with counterrotating rotors on Tomorrows World. It's really amazing seeing a toy containing so many technologies that were totally unavailable just a couple of decades ago.

[1] This is actually true for Duracell - their rechargeable batteries all seem to use the same cell, irrespective of the size.

So, what's the problem? gasoline is 10x as much energy dense as TNT. But then the comparison is kind of ridicules. TNT is designed to release all energy at once. A battery or gasoline, generally cannot do that. Gasoline can only do that under very specific circumstances. Batteries are even less likely to be destroyed as rapidly as openly burning gasoline.